The present invention relates to a vehicle control system designed to modify a response characteristic of a vehicle so as to make it easier for each individual driver to control the vehicle.
Generally, a motor vehicle has a steering system for steering the vehicle by responding to a steering input applied by a driver of the vehicle to a steering wheel, a brake system for decreasing the speed of the vehicle by responding to a brake input applied by the driver onto a brake pedal and an engine system for accelerating the vehicle by responding to an accelerator input applied to an accelerator pedal.
In typical conventional steering systems, a steering wheel is mechanically linked with front wheels. Japanese Patent Provisional (KOKAI) Publication No. 1-148660 discloses a steering system which includes both a mechanical steering linkage and an electric steering system. In typical conventional brake systems, a brake pedal is connected with a brake actuator by a brake hydraulic system. Some brake systems known as antiskid brake control systems (or wheel slip brake control systems) are designed to automatically control the degree of rotational wheel slip during braking. Some vehicles (BMW 750i) are equipped with a throttle-by-wire type accelerating system having an electronically controlled actuator for actuating a throttle valve.
However, these conventional systems take no account of the age and skill of each individual driver.
FIG. 20 shows human response characteristics (stimulus-response relationships) of human operators of various ages (disclosed in Magazine "NINGEN KOGAKU (Human Engineering)" Vol. 23, Special edition, pages 252-253 (D-2-10)). As to the response characteristic of a hand or foot of a human operator of the age greater than 60, a decline of the gain curve is steep over 0.1 Hz, and an increase of the phase delay is remarkable, as show in FIG. 20. Thus, the response characteristic of a human operator becomes worse as the age becomes higher.
Therefore, in an emergency, some of aged drivers are unable to steer the vehicle properly to circumvent an obstacle, or to brake the vehicle to avoid a collision, or to accelerate the vehicle properly.